I have been asked to bake a cake for a birthday party. At first, the cake was supposed to be a 9x 13. Well now the number of guests is in the area of 35-40 people. I have a 14x14 2" deep cake pan that I was going to use. I had planned on making two layers. But now I am wondering if I should go buy a bigger cake pan for this event. Any ideas on how many people would be fed by a 14 x14 2" deep pan? I thought 2" x 2" pieces of cake would be big enough...but others are telling me that would be too small????

Here's the chart straight from Wilton! I can't think right now. I usually make an 11x18 for that. It's kind of late and my math part of my brain is dead right now.
http://www.wilton.com/cake/cakeprep/baking/times/party_2inch.cfm

Using a 14 x 14 pan....if you cut the pieces in 2x2" squares, you can get 7 rows times 7 rows = 49 pieces. The 12x18 pan, cutting in 2x2" pieces would be 6 rows x 9 rows - 54 pieces, so you'd have some room for larger pieces.

remember that 2x2 is a 1 layer sheet cake if you are baking 2 14x 14 and making it 2 layer it will serve double the guests..... so if you are doing a 2 layer cake you could do the 9x13 and serve the crowd.